The pyrolytic decomposition of triethyl phosphate (TEP) has been studied at one atmosphere, from 706 to 854 K, in an isothermal quartz-lined, 4.5-cm-ID turbulent flow reactor with residence times between 15 and 85 ms. TEP was initially present at levels between 30 and 125 ppm, in N2. CO was used as an internal standard for mixing. Fourier-transform infrared spectrometry and gas chromatography/mass spectrometry preceded by conversion to trimethylsilyl derivatives were used to measure TEP and its products in samples extracted through quartz sampling tubes. Ethene, ethanol, diethyl phosphate, monoethyl phosphate, and orthophosphoric acid were observed as products. A multistep decomposition mechanism has been proposed, involving parallel pathways producing ethanol and ethene. Overall uni-molecular rate parameters for TEP decomposition have been obtained. Wall reactions affect the ethanol-to-ethene ratio, and may also affect the TEP decomposition rate.